Safety pen needle assembly

ABSTRACT

In one aspect, a safety pen needle assembly is provided herein which includes a hub with a needle fixed to the hub, the needle having a distal end, formed for insertion into a patient, and a proximal end. The assembly further includes a shield and a biasing member disposed between the hub and the shield configured to urge the shield distally. A protrusion extends from at least one of the hub and the shield with a channel being formed in at least the other of the hub and the shield. The channel is formed to accommodate the protrusion. The shield is movable from a first position to a second position. In the first position, the shield is spaced from the distal end of the needle such that the distal end of the needle is exposed. In the second position, the shield covers the distal end of the needle. The channel guides the protrusion as the shield moves from the first position to the second position. With this arrangement, a shield may be directed to move in a desired path with stability. In addition, the distal end of the needle may be initially exposed to permit visual confirmation of priming, while allowing the shield to cover a majority of the needle to minimize any needle-related anxiety.

BACKGROUND OF THE INVENTION

Safety pen needle assemblies are known in the prior art for providingshielding to a used pen needle to prevent inadvertent “needle sticks”therewith. These assemblies may be “passive”, which operate throughnormal use of the associated pen injector, or “active”, which require anadditional step or steps to operate beyond normal operation of theassociated pen injector.

Passive safety pen needle assemblies have been developed in the priorart which utilize a trigger that is activated upon sufficientapplication of force thereto during an injection procedure. A triggermay be provided which presses against a patient's skin with sufficientdisplacement of the trigger causing the assembly to activate. Theactivation of the trigger results in some form of a shield beingreleased which may move distally to a shielding position covering a usedneedle. With these designs, concerns exist of preventing inadvertenttrigger activation.

SUMMARY OF THE INVENTION

In one aspect, safety pen needle assembly is provided herein whichincludes a hub with a needle fixed to the hub, the needle having adistal end, formed for insertion into a patient, and a proximal end. Theassembly further includes a shield and a biasing member disposed betweenthe hub and the shield configured to urge the shield distally. Aprotrusion extends from at least one of the hub and the shield with achannel being formed in at least the other of the hub and the shield.The channel is formed to accommodate the protrusion. The shield ismovable from a first position to a second position. In the firstposition, the shield is spaced from the distal end of the needle suchthat the distal end of the needle is exposed. In the second position,the shield covers the distal end of the needle. The channel guides theprotrusion as the shield moves from the first position to the secondposition. With this arrangement, a shield may be directed to move in adesired path with stability. In addition, the distal end of the needlemay be initially exposed to permit visual confirmation of priming, whileallowing the shield to cover a majority of the needle to minimize anyneedle-related anxiety.

These and other features of the invention will be better understoodthrough a study of the following detailed description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-61 depict various safety pen needle assemblies, and componentsthereof, formed in accordance with the subject invention.

FIGS. 1-8 depict hubs or shields with channels that have moveableprotrusions;

FIGS. 9-14 depict hubs or shields with straight channels that allowshields to be manually rotated to a locking position;

FIGS. 15-16 depict hubs or shields with straight channels that allowshields to be manually urged in a distal direction to be locked;

FIGS. 17-23 depict hubs or shields that allow shields to beautomatically locked with a manual rotation;

FIGS. 24-25 depict a shield with locking tabs;

FIGS. 26-27 depict a shield or hub with a locking window and a curvedchannel;

FIGS. 28-32 depict depicts hubs or shields with straight channels thatallow shields to be manually rotated to a locking position;

FIGS. 33-35 depict a shield or hub with a locking window and a curvedchannel;

FIG. 35A depicts an alternative arrangement for a curved channel;

FIG. 36 depicts a safety pen assembly with a secondary shield on theproximal end;

FIGS. 37-43 depict a safety pen assembly with a secondary shield on theproximal end with one or more locking arms;

FIGS. 44-45 depict a secondary shield with one or more locking arms;

FIGS. 46-48 depict a hub or shield with locking features for thesecondary shield with one or more locking arms;

FIG. 49 depicts an alternate secondary shield for the proximal side withone or more locking arms;

FIG. 50 depicts a hub or shield with an alternative channel design;

FIGS. 51-52 depicts a plurality of channels and protrusions;

FIG. 53 depicts a shield with a plurality of integral protrusions andlocking windows;

FIG. 54 depicts a hub with a plurality of channels;

FIGS. 55-57 depict an alternative secondary shield for the proximal end;

FIGS. 58-59 depict a separate embodiment for securely covering theproximal end of the needle; and

FIGS. 60-61 depict embodiments for determining the depth of theprotrusion of a needle.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1-57B, a safety pen needle assembly 10 is shownwhich generally includes a hub 12, a shield 14, and a biasing element 16located therebetween. A needle 18 having a distal end 20, formed forinsertion into a patient during a medical injection, and a proximal end22 is provided and fixed to the hub 12. The safety pen needle assembly10 is configured to have the shield 14 cover the distal end 20 of theneedle 18 after use, i.e., after an injection.

The hub 12 includes a generally tubular body 24 having spaced apartdistal and proximal ends 26, 28. The tubular body 24, preferably inproximity to the proximal end 28, may be provided with a mountingarrangement (e.g., threads; luer) configured for mounting onto the bodyof a medical injector, e.g., a pen injector. A channel 30 is providedwhich may be formed in the hub 12 or the shield 14. With reference toFIGS. 1-8, the channel 30 may be formed in the tubular body 24 togenerally extend in a longitudinal direction from the distal end 26 tothe proximal end 28 of the tubular body 24. As shown in the figures, thechannel 30 may be a throughhole, which extends completely through thewall of the tubular body 24, or may be “blind” and be of limited depthin the tubular body 24 without extending therethrough. The channel 30may have various configurations. With reference to FIGS. 1-8, thechannel 30 may have a hook-, U- V-, J- or L-shape.

The shield 14 includes a distal end 32, having an aperture 34 (FIG. 5)formed therethrough, and a proximal end 36. The shield 14 may be ofvarious configurations, as will be appreciated by those skilled in theart.

A protrusion 38 may be provided on the hub 12 or the shield 14, formedto be accommodated in the channel 30. With reference to the embodimentof FIGS. 1-8, the protrusion 38 projects from the shield 14. The biasingelement 16 is disposed to urge the shield 14 distally. Under force ofthe biasing element 16, the protrusion 38 is preferably urged to thedistalmost portion of the channel 30. The interengagement of theprotrusion 38 and the tubular body 24, at the end of the channel 30,limits distal movement of the shield 14 relative to the hub 12.

Prior to use, the shield 14 is configured to be in an initial pre-usestate. In this pre-use state, the shield 14 may be configured to coverthe distal end 20 of the needle 18 (FIG. 4) or may be configured toleave the distal end 20 exposed (FIG. 28). The initial state of coverageof the distal end 20 may be determined by user preference. With thedistal end 20 being initially covered, the needle 18 is not visible,thereby minimizing anxiety, particularly for a needlephobe.Alternatively, with the distal end 20 being exposed, a user may visuallyconfirm proper priming and needle placement during an injection. Evenwith the distal end 20 being exposed, a majority of the needle 18 maystill be covered to minimize anxiety.

During use, the shield 14 is caused to move proximally while pressedagainst a patient's skin, against the force of the biasing element 16.With sufficient pressure, the needle 18, passing through the aperture34, enters the patient's skin the required depth and an injection isadministered as is well known in the art. The shield 14 is urgedproximally during this procedure. During this proximal movement, theprotrusion 38 is guided by the channel 30. After injection, and removalof the shield 14 from the patient, the biasing element 16 urges theshield 14 distally to a position where the distal end 20 of the needle18 is covered. The safety pen needle assembly 10 may be provided with alocking arrangement to lock the shield 14 in the final, shieldedposition covering the distal end 20. As appreciated by those skilled inthe art, various locking arrangements are useable with the subjectinvention.

By way of non-limiting example, and with reference to FIGS. 1-8, thechannel 30 is shown to have a general V-shape which permits for alocking arrangement. Specifically, a flexible finger 40 extends into thechannel 30 which is inherently biased to extend towards a first edge 42located along the channel 30. A gap 44 is defined between the flexiblefinger 40 and the first edge 42 which is sized to normally have adimension smaller than the width of the protrusion 36. The gap 44 may benegligible or non-existent with the flexible finger 40 contacting thefirst edge 42. During use, the protrusion 38 is initially located to bein a first part 46 of the channel, which is located along the first edge42. With the shield 14 being urged proximally, the protrusion 38 isurged proximally along the first part 46 and towards the gap 44 (FIG.5). The protrusion 38 with sufficient proximal movement is forcedthrough the gap 44, with the flexible finger 40 being deflected. Afterpassage through the gap 44, the flexible finger 40 returns to itsnatural state (FIG. 6). The protrusion 38 passes through the gap 44during the injection procedure (i.e., while the needle 18 is insertedinto a patient the required depth for injection). In this manner, theshield 14 may be retracted to a limited depth (i.e., a depthcorresponding to the protrusion 38 not passing through the gap 44)without activating the device. Once the protrusion 38 passes through thegap 44, the protrusion 38 cannot return to the initial state.

Upon the shield 14 being removed from a patient's skin, the biasingelement 16 causes the shield 14 to move distally. As a result, theflexible finger 40 deflects the protrusion 38 into a second part 48 ofthe channel 30 (FIG. 7). To lock the shield 14 in the shieldingposition, a locking aperture 50 may be defined in the tubular body 24 ofthe hub 12 (FIG. 8). The locking aperture 50 may be located proximallyof the second part 48 and may be formed to receive in snap engagementthe protrusion 38. Under force of the biasing element 16, with theshield 14 being completely removed from a patient's skin, the shield 14may be urged distally with the protrusion 38 coming into snap engagementwith the locking aperture 50. A ridge 52 may be defined between thesecond part 48 and the locking aperture 50 which inhibits the protrusion38 from re-entering the channel 30 and allowing the shield 14 to retractproximally. The biasing element 16 must generate sufficient biasingforce to urge the protrusion 38 past the ridge 52 with this arrangement.Alternatively, the protrusion 38 may be urged to a distalmost portion ofthe second part 48 under force of the biasing element 16, and theprotrusion 38 may be then manually urged into the locking aperture 50 byforcing the shield 14 a sufficient distance to permit the protrusion 38to snap engage the locking aperture 50. The ridge 52 may be internallyramped or curved on a proximal edge to facilitate the protrusion 38passing thereby.

To permit the distal end 20 of the needle 18 to be initially exposed,but later fully shielded, the locking aperture 50 may be located to bemore distal of the distalmost portion of the first part 46 of thechannel 30, as shown in FIGS. 1-8. In this manner, in a final shieldingstate, the shield 14 is permitted to extend more distally from the hub12, than in the initial state, where the protrusion 38 is received inthe distalmost portion of the first part 46. Optionally, or in thealternative, the second part 48 may extend more distally than the firstpart 46, likewise allowing the needle 18 to be initially exposed, butlater fully shielded. This may be in addition to, or as an alternativeto, locating the locking aperture 50 more distal than the distalmostportion of the first part 46.

As will be appreciated by those skilled in the art, any number ofprotrusions 38 and the channels 30 may be used consistent with thesubject invention. Likewise, any number of elements discussed withrespect to the other features may likewise be used in various quantitiesin conjunction with the subject invention.

Further, as will be appreciated by those skilled in the art, theprotrusion 38 may be formed on the hub 12 with the channel 30 beingformed on the shield 14, for example, as shown in FIGS. 9-14. As such,the channel 30 may move relative to the protrusion 38. Preferably, theshield 14 is located inside of the hub 12 where the protrusion 38 isformed on the shield 14. Also, preferably, the shield 14 is locatedexternally of the hub 12 where the protrusion 38 is located on the hub12.

In an alternate configuration, and with reference to FIGS. 9-23, thechannel 30 may be straight and parallel to a longitudinal axis of thepen needle assembly 10. The straight shape of the channel 30 allows theprotrusion 38 to move back and forth, proximally and distally. Differentlocking arrangements are available for use with this configuration. Withreference to the configuration of FIGS. 9-14, after use, the shield 14may be manually rotated to have the protrusion 38 snap engage with thelocking aperture 50.

With reference to FIGS. 15-16, the locking aperture 50 may be locatedlongitudinally spaced from the channel 30 in a proximal direction. Withthis arrangement, after use, the shield 14 may be urged manually in adistal direction with the protrusion 38 snap engaging the lockingaperture 50.

With reference to FIGS. 9-16, the protrusion 38 may be initially seatedin the channel 30 without any locking thereof. As such, the protrusion38 may be freely movable before use. Optionally, a cover 53, having atleast one inwardly extending element 55, may be provided configured tohave the element 55 prevent the channel 30 from moving proximallyprematurely. In addition or alternatively, the protrusion 38 may bereleasably locked prior to use. For example, with reference to FIGS.9-14, the protrusion 38 may be seated in the locking aperture 50 beforeuse. To use the assembly 10, the shield 14 is manually rotated to urgethe protrusion 38 into the channel 30. After use, reverse manualrotation of the shield 14 returns the protrusion 38 into snap engagementwith the locking aperture 50.

The arrangements of FIGS. 9-16 require manual intervention to achievelocking. To avoid manual locking, and with reference to FIGS. 17-23, thechannel 30 may have the first part 46 disposed transversely relative tothe second part 48 which is parallel to the longitudinal axis of the penneedle assembly 10. In an initial state, as shown in FIG. 19, theprotrusion 38 is seated in the channel 30, particularly the first part46, to prevent proximal or distal movement of the shield 14 relative tothe hub 12. With manual rotation of the shield 14, the protrusion 38 ismoved through the first part 46 of the channel 30 and into the secondpart 48 (FIG. 20), where the shield 14 is free to move distally underforce of the biasing element 16. The biasing element 16 is selected suchthat sufficient force is provided to force the protrusion 38 from thechannel 30 (FIG. 21) and into snap engagement with the locking aperture50 after use (FIG. 22). Preferably, with this arrangement, the shield 14is not rotated until the needle 18 has been removed from a patient'sskin after an injection. To enhance the user's ability to rotate theshield, textured regions 54 (FIG. 11) may be provided on the tubularbody 24 and/or outwardly projecting wings 56 (FIG. 23) may be provided.In addition, the cover 53 (FIG. 17), having the at least one inwardlyextending element 55, may be provided configured to have the element 55prevent the protrusion 38 from entering the second part 48 prematurely.

The safety pen needle assembly 10 may be configured to have anautomatically rotating arrangement where the shield 14 movesrotationally relative to the hub 12, such as to achieve locking, withoutmanual intervention beyond the normal injection procedure. Withreference to FIGS. 24-25, the shield 14 may be provided with a lockingtab 58 in addition to the protrusion 38. Correspondingly, locking window60 may be formed in the tubular body 24 (FIGS. 26-27) formed to receivethe locking tab 58. With reference to FIGS. 28-32, the arrangement ofthe channel 30, with the flexible finger 40, as described above, may beutilized. With reference to FIGS. 33-35, the protrusion 38 moving fromthe first part 46 to the second part 48 of the channel 30, the shield 14is caused to rotate relative to the hub 12. With the protrusion 38moving through the second part 48 of the channel 30, the locking tab 58and the locking window 60 are configured such that the locking tab 58snap engages the locking window 60 and, thus, locks the shield 14. Tofacilitate proper operation of this locking arrangement, cantileveredtongues 62 may be defined in the tubular body 24 proximally of thelocking windows 60 to allow resilience with the locking tabs 58traversing thereacross. As discussed above, with the second part 48being formed longer than the first part 46, the shield 14 may permitexposure of the distal end 20 of the needle 18 prior to use (FIG. 28)with full shielding thereof after use (FIG. 32).

As will be appreciated by those skilled in the art, the shape of thechannel 30 directs the rotation of the shield 14. With reference toFIGS. 1-8, the first part 46 may be formed generally parallel to thelongitudinal axis of the pen needle assembly 10. Accordingly, the shield14 does not rotate with the protrusion 38 passing through the first part46. Rotation is caused with the protrusion 38 passing through the secondpart 48, which is disposed transversely to the longitudinal axis of thepen needle assembly 10. Alternatively, as shown in FIG. 50, the firstpart 46 may be disposed transversely to the longitudinal axis of the penneedle assembly 10. As such, the shield 14 will rotate with theprotrusion 38 traversing the first part 46—this results in the shield 14rotating during insertion of the needle 18 into a patient. Rotation maybe desired through both the first and second parts 46, 48. By angularlyarranging the first and second parts 46, 48, rotation of the shield 14may be controlled.

With reference to FIGS. 33-35, as an alternative to the flexible finger40, the channel 30 may be provided with a stationary finger 64separating the first part 46 from the second part 48. To ensure that theprotrusion 38 moves into the second part 48 properly, it is preferredthat the protrusion 38 be initially urged in the opposite direction fromthe desired rotational direction, while traversing the first part 46.For example, with reference to FIGS. 33-35, the stationary finger 64 isshown to be bent towards the left. As the protrusion 38 is urgedproximally, the protrusion 38 also rotates to the left. In this manner,a torsional force is generated in the biasing element 16 which urges theprotrusion 38 in a rightward direction. Preferably, the amount ofrotation of the shield 14 (i.e., rotation of the protrusion 38) islimited during the injection. The travel of the protrusion 38 throughthe first part of the channel 30 coincides with the injection process.With the second part 48 being hook-shaped, once the protrusion 38 passesthe stationary finger 64 and is under force of the generated torsionforce, the protrusion 38 is urged into the second part 48. Theprotrusion 38, however, preferably does not traverse the second part 48until after the injection, particularly after removal of the pen needleassembly 10 from the patient's skin. Upon removal of the shield 14 fromthe patient's skin, the biasing element 16 urges the shield 14 distallywith the protrusion 38 traversing the second part 48. The lockingarrangement as described above with the locking tab 58 and the lockingwindow 60 may be utilized with this configuration.

FIG. 35A depicts an alternate arrangement for the channel 30 where thestationary finger 64 is generally straight. In this arrangement, as thepen needle assembly 10 is removed from the patient's skin, the shield 14advances linearly through the first part 46, and the protrusion 38contacts angular surfaces 39 a, 39 b, directing the protrusion 38 alongthe channel 30 into the second part 48. A locking arrangement may beutilized herewith such as, with angular surface 39 c being provided todirect the protrusion 38 into the locking window 60. The angularsurfaces 39 a, 39 b, 39 c may be formed with straight and/or arcuatesections.

As depicted in FIGS. 51-54, a plurality of the channels 30 (30A, 30B, .. . ) and a plurality of the protrusions 38 (38A, 38B, . . . ) may beutilized. The entire circumference of the hub 12 and the shield 14 maybe provided with the channels 30 and the protrusions 38.

The channels 30 may be provided in a repeated pattern with likeconfigurations. As shown in FIG. 51, the channels 30 may have differentconfigurations, such as the channels 30A, 30B. The channel 30B includesthe first part 46 and the second part 48 separated by the stationaryfinger 64. The first channel 30A is shown to include the first part 46and the second part 48, with the angular surfaces 39 a, 39 b, but withno separating finger. With movement of the protrusion 38B about thestationary finger 64, the protrusion 38A moves simultaneously along thechannel 30A. As shown in dashed lines, in a final state, the protrusions38A, 38B are located adjacent the ridges 52 (52A, 52B). The ridges 52are positioned so as to limit axial movement in either axial direction.For example, the protrusion 38A is located above the ridge 52A while theprotrusion 38B is located below the ridge 52B. The collective effect ofthis arrangement is to prevent axial movement, proximally or distally.

Angled surface 39 c may be provided to restrict backward movement of theprotrusion 38A (and possibly movement out of a locked position). Toenhance this restrictive effect, gap 41 may be defined adjacent to theangled surface 39 c. Preferably, the gap 41 is smaller than the diameterof the protrusion 38A. In addition, the stationary finger 64 and/or theangled surface 39 c may be defined to be deflectable, as shown in dashedlines. By being formed deflectable, the stationary finger 64 and theangled surface 39 c further resist backward movement of the protrusions38A, 38B.

In some embodiments, as set forth in FIGS. 53-54, the shield 14 may bemolded with a plurality of integral protrusions 38 along the lower edge15 of the inside diameter. If desired, the top edge of the shield 14 maybe provided with a plurality of openings 43 for each protrusion 38 tofacilitate formation of the protrusion 38, particularly by molding. Theprotrusions 38 may be incorporated as a part of a latch feature 45,which is designed to flex as it passes over tapered leads or otherraised sections of the channels 30 to engage with the body of the hub 12and be properly positioned in the channels 30 ready for use.

As will be appreciated by those skilled in the art, the safety penneedle assembly 10 may be utilized with other features, including ashielding arrangement for shielding the proximal end 22 of the needle 18after use. With reference to FIGS. 36-49, the arrangement of the channel30 generally discussed with respect to FIGS. 1-8 is shown. In addition,a secondary shield 66 is shown. The secondary shield 66 includes one ormore locking arms 68 that pass through openings 71 of bulkhead 70 formedin the tubular body 24 of the hub 12. The locking arms 68 each include adetent 72 which latches onto a portion of the bulkhead 70 in a pre-usestate. As shown in FIGS. 37-40, the proximal end 22 of the needle 18 isexposed during use.

Preferably, the detent 72 includes a ramped surface 74 which facesgenerally distally. An angled engagement surface 76 is formed on theproximal end 36 of the shield 14 in axial alignment with the rampedsurface 74. The ramped surface 74 and the engagement surface 76 areconfigured and arranged such that, upon sufficient proximal movement ofthe shield 14, the engagement surface 76 presses against the rampedsurface 74 and causes outward displacement of the ramped surface 74.With sufficient outward displacement, the detent 72 unlatches from thebulkhead 70. The biasing element 16 may be located between the lockingarms 68 and the shield 14 such as in a retaining channel 78. With thelocking arms 68 being unlatched, the secondary shield 66 is free to moveproximally under force of the biasing element 16. As shown in FIG. 42,the secondary shield 66 is urged to a shielding position where theproximal end 22 of the needle 18 is covered. The secondary shield 66 isfree to move upon removal of the pen needle assembly 10 from an injectorbody B (FIG. 55). To lock the secondary shield 66 in this shieldingposition, one or more of the locking tabs 58 may be provided on thesecondary shield 66 with an associated number of the locking windows 60being formed in the tubular body 24. With the locking tabs 58 being insnap engagement with the locking windows 60, proximal or distal movementof the secondary shield 66 is limited. Alternatively, and with referenceto FIGS. 55-57, the locking arms 68 may be formed with at least onesecondary locking tab 86 and at least one tertiary locking tab 88. Asshown in FIGS. 57A and 57B, the secondary locking tabs 86 and thetertiary locking tabs 88 are located on different locking arms 68 andspaced apart so as to sandwich the bulkhead 70 therebetween. During use,the bulkhead 70 is snap received in the collective gap formed by thesecondary and tertiary locking tabs 86, 88. The secondary locking tabs86 may be defined by the detents 72.

In addition, as shown in FIG. 56B, one or more latches 90 may beprovided in addition to the locking arms 68 for latching the secondaryshield 66 to the bulkhead 70 prior to use. The detents 72, with theramped surfaces 74, may be formed on the latches 90, in addition, oralternatively, to the locking arms 68.

With reference to FIGS. 58 a-59, a further useable shield for coveringthe proximal end 22 of the needle 18 is depicted. Here, a leafspring 100is utilized which is secured to the pen needle assembly 10, preferablyat the hub 12. As shown in FIG. 58 a, the leafspring 100 in a pre-usestate is configured to be spaced from the proximal end 22 of the needle18. Preferably, the leafspring 100 is retained by a frangible connection102. With reference to FIG. 58, it is preferred that the connection 102rupture upon the pen needle assembly 10 being mounted onto the injectorbody B. For example, the hub 12 may be formed with a slightly smallerinner diameter, which expands upon being mounted, thus causing ruptureof the connection 102.

As shown in FIG. 59, the leafspring 100 is formed with inherent memoryto cover the proximal end 22 of the needle 18. Thus, with the connection102 being ruptured, and the pen needle assembly 10 being removed fromthe injector body B, the leafspring 100 is free to move and shield theproximal end 22. Inherent resilience of the leafspring 100 shall causethe leafspring 100 to remain over the proximal end 22.

As will be appreciated by those skilled in the art, the leafspring 100may be formed of various materials which provide internal resilience tourge the leafspring 100 to the shielding state. Preferably, theleafspring 100 is formed of a thermoplastic material and more preferablyformed unitarily with the hub 12. Biasing force to urge the leafspring100 to the shielding state may be generated about junction 104 formed atthe intersection of the leafspring 100 and the pen needle assembly 10.Preferably, free end 106 of the leafspring 100 biases outwardly uponrupture of the connection 102 to be clear of other portions of the penneedle assembly 10. In this manner, the free end 106 is urged by thebiasing force generated about the junction 104 to cover the proximal end22 of the needle 18.

Preferably, the various locking apertures or windows discussed above forreceiving in snap engagement a locking element (e.g., the lockingaperture 50; the locking window 60) are preferably through holes whichextend through a respective surface to permit visual confirmation of alocked arrangement from an external vantage point. The apertures orwindows may be formed blind with limited depth so as to not fully extendthrough a respective surface. This is less desirable since visualconfirmation may not be achievable. However, an audible or tactile clickmay be relied to indicate snap engagement.

As depicted in FIGS. 60A-60C, the present invention may include one ormore indicia for determining the depth of protrusion (insertion) of theneedle 18 into the patient's body. This may be important, for example,when the medication being injected is desirably administered to aparticular depth into the body of the patient. The invention may includean outer shield assembly 120 that is slidably attached to the outersurface 128 of a portion of a medical injector, preferably the outersurface 128 of a needle assembly (e.g. the outer surface of the hub 12).The outer shield assembly 120 may include a small diameter cylinder 122,which is offset from the axis of the needle 18. At the top of thecylinder 122 is a shield portion 124, which may cantilever from thecylinder 122. The cylinder 122 may include one or more depth markings126 to allow control of the insertion depth of the needle 108.

In this embodiment, as the distal end 20 of the needle 18 is insertedinto the skin of the patient, the outer shield assembly 120 is pressedby a patient's skin and moved away from the distal end 20 of the needle108 down the outer surface 128 of the assembly. As the outer shieldassembly 120 is pressed down by the patient's skin, the depth markings126 are likewise pressed down away from the distal end 110 of the needle18. The user can thus view the depth markings 126 as the needle 18 isinserted into the skin, or after injection, and determine the properinsertion depth for the needle 18.

If desired, the outer shield assembly 120 may provide a shield for thedistal end 110 of the needle 18 after use. The shield portion 124 may beformed to cover the distal end 110 of the needle 18. The shield portion124 may be manually adjusted after use to cover the distal end 20.Preferably, the outer shield assembly 120 includes a spring 130, whichbiases the outer shield assembly 120 along the outer surface 128 of theassembly towards the distal end 20 of the needle 18. Prior to use, theouter shield assembly 120 may be disposed such that the distal end 20 ofthe needle 18 is exposed (FIG. 60A). During use, the distal end 20 ofthe needle 18 is pressed into the skin of the patient, thus forcing theouter shield assembly 120 down along the outer surface 128 of theassembly (FIG. 60B). Once the injection is complete, the needle 18 isremoved from the skin of the patient. As the force of the skin againstthe outer shield assembly 120 is removed, the spring 130 forces theouter shield assembly 120 towards the distal end 20 of the needle 18,covering the tip of the distal end 20 (FIG. 60C). If desired, the outershield assembly 120 may include a locking arrangement to secure theouter shield assembly 120 in place once it has covered the distal end 20of the needle 18.

It will be understood by those of skill in the art that the cylinder 122need not have a circular cross-section, rather it may be oval,ellipsoidal, or any other shape that matches up to the outer surface 128of the assembly. For example, the cylinder 122 may be crescent shaped soas to aid in the sliding engagement with the outer surface 128 of theassembly. Further, the shield 124 need not completely surround theneedle, and may include two prong-like arms that extend alongside thedistal end 110 of the needle 108, preventing accidental contact.

The depth markings 126 may include a series of markings on the cylinder122, or may include one single depth mark that is used to indicate thatthe needle 18 has been inserted the proper depth into the patient.Alternatively, a single depth mark may indicate that the needle 18 hasbeen inserted a sufficient distance to engage the safety mechanism ofthe outer shield assembly 120 (i.e., the spring has been depressedenough to allow the shield portion 124 to cover the distal end 20 of theneedle). The depth markings 126 may be etched into the cylinder 122, orthey may be drawn onto the cylinder 122 with ink or any suitablematerial.

In an alternate embodiment, the outer shield assembly 120 may include anadditional protruding member parallel to the cylinder 122 such that theouter shield assembly 120 rests along the outside of the hub. In thiscase, the hub may be restrained and move between the cylinder 122 andprotrusions.

As will be appreciated by those skilled in the art, the various featuresdescribed herein may be used in various combinations. For example, andwith reference to FIG. 61, the non-patient shield may be used inconjunction with the depth markings and shield.

1. A safety pen needle assembly comprising: a hub; a needle fixed tosaid hub, said needle having a distal end, formed for insertion into apatient, and a proximal end; a shield; and, a biasing means disposedbetween said hub and said shield configured to urge said shielddistally, wherein, a protrusion extends from at least one of said huband said shield, a channel is formed in at least the other of said huband said shield, said channel formed to accommodate said protrusion,wherein said shield is movable from a first position to a secondposition, wherein, in said first position, said shield is spaced fromsaid distal end of said needle such that said distal end of said needleis exposed, wherein, in said second position, said shield covers saiddistal end of said needle, and wherein said channel guides saidprotrusion as said shield moves from said first position to said secondposition; whereby when said shield is in said first position, a user mayvisually confirm proper priming and needle placement during use.
 2. Theneedle assembly of claim 1, wherein said channel is generally U-shaped,V-shaped, J-shaped, or hook-shaped.
 3. The needle assembly of claim 1,wherein said channel has a proximal and a distal end, and wherein underforce of said biasing means, said protrusion is urged towards saiddistal end of said channel.
 4. The needle assembly of claim 1, furthercomprising a locking means to lock said shield in said second position.5. The needle assembly of claim 4, wherein said shield may be locked insaid second position through manual manipulation by said patient.
 6. Theneedle assembly of claim 4, wherein a locking tab extends from at leastone of said hub and said shield, a locking window is formed in at leastthe other of said hub and said shield, wherein said locking tab engagessaid locking window when said shield is in said second position.
 7. Theneedle assembly of claim 1, wherein said channel comprises a first partand a second part, wherein said protrusion is located in said first partof said channel prior to use and wherein said protrusion is located insaid second part of said channel after use.
 8. The needle assembly ofclaim 7, wherein a flexible finger extends into said channel whichextends across an axis extending from said first part of said channel.9. The needle assembly of claim 8, wherein during use, said flexiblefinger deflects said protrusion into said second part of said channel.10. The needle assembly of claim 7, wherein the distalmost portion ofsaid second part of said channel is located distally of the distalmostportion of said first part of said channel.
 11. The needle assembly ofclaim 10, wherein a locking tab extends from at least one of said huband said shield, a locking window is formed in at least the other ofsaid hub and said shield, wherein said locking tab engages said lockingwindow when said shield is in said second position, and wherein saidlocking window is located more distally than the distalmost portion ofsaid first part of said channel.
 12. The needle assembly of claim 7,wherein a locking tab extends from at least one of said hub and saidshield, a locking window is formed in at least the other of said hub andsaid shield, wherein said locking tab engages said locking window whensaid shield is in said second position, and wherein said locking windowis located more distally than the distalmost portion of said first partof said channel.
 13. A safety pen needle assembly comprising: a hub; aneedle fixed to said hub, said needle having a distal end, formed forinsertion into a patient, and a proximal end; a shield; and, a biasingmeans disposed between said hub and said shield configured to urge saidshield distally, wherein a protrusion extends from at least one of saidhub and said shield, a channel is formed in at least the other of saidhub and said shield, said channel formed to accommodate said protrusion,wherein said shield is movable from a first position to a secondposition, wherein, in said first position, said shield covers saiddistal end of said needle, wherein, in said second position, said distalend of said needle is exposed, and wherein said channel guides saidprotrusion as said shield moves from said first position to said secondposition; and, wherein said shield is initially in a locked state withsaid protrusion being spaced from said channel, said shield beingmanually movable out of said locked state to urge said protrusion intosaid channel thereby allowing said shield to move from said firstposition to said second position.
 14. The needle assembly of claim 13,wherein a locking aperture is formed in at least one of said hub andsaid shield formed to accommodate in snap engagement said protrusion insaid locked state, said locking aperture being spaced from said channel.15. The needle assembly of claim 13, wherein said shield is rotatableout of said locked state.
 16. The needle assembly of claim 13, whereinsaid shield is axially displaceable out of said locked state.
 17. Asafety pen needle assembly comprising: a hub; a needle fixed to saidhub, said needle having a distal end, formed for insertion into apatient, and a proximal end; an axially-displaceable shield for coveringsaid distal end of said needle, said shield having an angled engagementsurface defined thereon; a secondary shield for covering said proximalend of said needle, said secondary shield having at least one detentwith a ramped surface formed thereon in axial alignment with said angledengagement surface; and, a biasing means disposed to urge said secondaryshield proximally, wherein, said detent releasably retains saidsecondary shield in a first state with said proximal end of said needlebeing exposed, and, wherein, with sufficient proximal movement of saidshield, said engagement surface engages said ramped surface and causesdisplacement of said detent thereby releasing said secondary shield fromsaid first state and allowing said biasing means to urge said secondaryshield proximally.
 18. The needle assembly of claim 17, wherein saidsecondary shield includes one or more elongated locking arms, saiddetent being formed on said locking arm.
 19. The needle assembly ofclaim 18, wherein one or more locking tabs being configured on saidlocking arms so as to collectively snap receive a portion of said hub.20. A safety pen assembly comprising: a hub; a needle fixed to said hub,said needle having a distal end, formed for insertion into a patient,and a proximal end; and, a leafspring secured to said hub by a frangibleconnection, said frangible connection being rupturable, wherein, withrupture of said frangible connection, a free end of said leafspring isurged to cover said proximal end of said needle.
 21. A medical injectorcomprising: a needle; and, a slidable body disposed adjacent to saidneedle, said body having depth marks defined thereon, wherein during aninjection of said needle into a patient, said slidable body is depressedby the patient's skin, said depth marks indicating the extent ofdepression of said body during the injection thereby providing anindication of depth of injection by said needle.